Identification and evolutionary relationships of partial gene sequences from dehydrin group in three species of cacti

Abstract

Dehydrins or Group 2 Late Embryogenesis Abundant (LEA) proteins play an important role in the response and adaptation to different types of abiotic stresses such as droughts, high salinity and low temperatures. Using PCR techniques, we identified three gene fragments that encoded dehydrin-like proteins in three cactispecies Opuntia ficus-indica (OpfiDHN-like), Leuchtenbergia principis (LepDHN-like) and Mammillaria bombycina (MabDHN-like). Bioinformatic sequence analysis showed an identity between 96 and 97% with the Opuntia streptacantha dehydrin 1 (OpsDHN1) gene, demonstrating that the amplified fragments corresponded to dehydrin-like gene sequences, and that the designed oligonucleotides were effective for similar gene amplification in different cacti genera. Multiple OpfiDHN-like, LepDHN-like and MabDHN-like alignments showed that they possessed three repetitions of the conserved K segment. Also, a histidine rich motif was found, which is believed to facilitate the binding of these proteins with metal ions that probably evolved differently in the Opuntioidea and Cactoidea subfamilies of the Cactaceae family. Bioinformatic tools demonstrated that each of the three partial amino acid sequences corresponded to acidic, highly hydrophilic, and disordered protein fragments, which are characteristics of dehydrin proteins. Phylogenetic analysis using maximum parsimony, indicated that cacti dehydrins-like proteins were monophyletic, as well as those of other families.